Tube drawing process



Aug. 10, 1965 H. BRAUER TUBE DRAWING PROCESS 6 Sheets-Sheet 1 Original Filed Sept. 4, 1962 INVENTOR HANS BRAUER ATTORNEY Aug. 10, 1965 H. BRAUER TUBE DRAWING PROCESS 6 Sheets-Sheet 2 Original Filed Sept. 4. 1962 INVENTOR HANS BRAUER ATTORNEY Aug. 10, 1965 r H. BRAUER 3,199,332

TUBE DRAWING PROCESS Original Filed Sept. 4, 1962 6 Sheets-Sheet 3 INVENTOR HANS BRAUER Aug. 10, 1965 H. BRAUER 3,199,332

TUBE DRAWING PROCESS Original Filed Sept. 4, 1962 e Sheets-Sheet 4 INVENTOR HANS BRAUER ATTORNEY Aug. 10, 1965 Original Filed Sept. 4, 1962 H. BRAUER TUBE DRAWING PROCESS 6 Sheets-Sheet 5 INVENTOR HANS BRAUER ATTORNEY Aug. 10, 1965 H. BRAUER 3,199,332

TUBE DRAWING PROCESS Original Filed Sept. 4, 1962 6 Sheets-Sheet 6 INVENTOR HANS BRAUER BY al/MM ATTORNEY United States Patent Ofi ice Patented Aug.

The present invention relates to the manufacture of is application is a division of my copending application Seri 1 No. 221,658, filed September 4, i962 and entitled Tube Drawing Process and Apparatus.

At the present time it is possible to provide in a relatively efiicient manner and with a fairly satisfactory output tubes which may be either seamles or which may ha 'e welded seams. However, after such tubes are initially formed, it is very often necessary to work the tubes further so as to provide them with desired inner and outer diameters. l his involves moving the tubes through a drawing pass while maintaining mandrels in the tubes so as to provide the tubes eventually with the desired dimensions, several drawing passes often being required before the final dimensions of the tubes are reached. At the present time after each drawing pass it is necessary to transport the tubes back around to the starting position for the next drawing pass, and invariably these operations require movement of the tubes out of the drawing plane at one part thereof and back into the drawing plane at another part thereof in preparation for the next-following pass. These tubes are usually manufactured in long lengths which may be of the order of 50 meters, and of course the length of the tube increases at each successive pass thereof, so that. particularly in the case of nonferrous tubes, bending and other injury to the tube, such as denting of the wall thereof, can easily occur, and particularly during the final passes it may not be possible to remove these defects froi the tubes.

it is accordingly a primary object of the present invention to provide a tube-drawing process and apparatus which will reliably avoid injury to the tubes during transportation thereof between successive passes.

Another object of the present invention is to provide a tube drawing process and apparatus capable of carrying out the successive passes without changing the position of the of a tube so that the operations can be carried out with the process and apparatus of the invention in a space far less than that required for a conventional process and apparatus.

it is also an object of the invention to provide a process and apparatus enabling a tube to be reciprocated back and forth along its axis during the operations required for successive drawing passes so that the time required for these operations is also reduced as compared to a or -ventional process and apparatus, and thus the output with the process and apparatus of the invention is greater than that possible with conventional process and apparatus.

A further object of the present invention is to provide a relatively simple rugge structure capable of being incorporated into conventional tube drawing apparatus and capable of accomplishing the above results.

With the above objects in view the invention includes in a tube drawing process, the steps of drawing a tube with i s axis in a predetermined position through successive dies during successive drawing passes while mandrels appropriate to said dies are respectively in the tube, and between each pair of successive passes moving the tube in a directlon reverse to the drawing direction onto the ill mandrel appropriate to the next drawing pass without changing the position of the tube axis, so that in this way it is possible to carry out the drawing operations while the tube remains with its axis stationary in the drawing plane.

Also, the invention includes an apparatus in which the dies for the successive passes are carried by a rotary diecarrying means which is turnable for locating the dies successively in the drawing plane, the mandrels being carried by a rotary mandreLcarrying means which is capable of being turned to position the appropriate man- 'rels successively in the drawing plane, and in accordance with the invention a means is provided for moving each tube after one drawing pass in a reverse direction onto the mandrel appropriate to the next drawing pass without changing the position of the axis of the tube, the rotary die-carrying means being formed with a suitable cutout through which the tube can move during its reverse movement onto the mandrel for the next-following pass.

The novel features which are considered as characteristie for the invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings, in which:

FFGS. la and lb show, respectively, adjoining portions of a tube drawing apparatus, in a schematic side elevation, at that part of the apparatus which is provided with the structure of the invention;

PEG. 2 is a transverse sectional view of the apparatus taken along the line 22 of FIG. 1b and showing structure used before and after the tube drawing operations are performed as well as part of the structure used during the tube drawing operations;

FIG. 3 is a sectional view taken along the line 3-3 of PEG. 1b in the direction of the arrows and showing the rotary die-carrying means as well as structure associated therewith;

FIG. 4 is a transverse sectional view taken along the line d-4 of FIG. 1b in the direction of the arrows and showing the rotary mandrel-carrying means and structure associated therewith; and

FIG. 5 is a sectional schematic elevation showing details of the rotary mandre -carrying means.

Referring to the drawings, there is shown in FiGS. 1b, 4 and 5 the rotary mandrel-carrying means 1 in the form of a rotary drum supporting the several sets of mandrels 2a, 2b, 2c, 242 required for the successive drawing passes, these mandrels being shown particularly in FIG. 4. Thus it will be seen from FIG. 4, there are, in the illustrated example, four sets of three mandrels each, with these sets being used in the successive drawing passes, as described below. The tubes 3 which are to be drawn are initially located on suitable guide-ways at the upper part of the apparatus, as indicated in the upper part of FIG. 2. The roll pairs 3, 4a and 5, 5a shown at the upper part of FIG. 1b engage the tubes and transport them automatically in a known way to the right, as viewed in FIG. 11), onto the mandrels 2a, respectively, which are to be used during the first drawing pass, these mandrels being located between the roll pairs 6, 6a, as shown in Fl. 15. FIG. 3 shows at its upper portion the three sets of roll pairs 4-, 4a which engage the tubes and transfer them to the sets 5, 5:; from which they are transferred to the sets 6, do while passing onto the first mandrels 2a, respectively. Four sets of rolls 5a, with three rolls to each set, and four sets of rolls 5a with three rolls to each set are carried by the drum 1, and the several sets are displaced by with respect to each other about the drum axis, as is apparent from the rolls 5a shown in FIG. 4. The several rolls 6a are located directly behind the rolls 5a which are visible in FIG. 4. The rolls 5a and 6a. which are in the uppermost position cooperate with rolls 5 and 6 which do not turn ,with the drum 1, while the rolls 5a and 6a atthe lower part of the drum cooperate with the rolls '12 and 12a, respectively, as indicated most clearly in FIG. 5. Each roll 6a is turnablycarried by one end of the bell crank (FIG. 5) capable of being adjusted by axial movement of a piston 8 which can be moved by manual turning of a hand wheel 7, the several units 7, 8 being carried by the drum 1 and cooperating with the several, bell cranks which respectively carry the rolls 641, so that by turnin the hand- Wheels 7 the operator can adjust the positions of the wheels 6a. Each handwheel 7 may be fixed to a rotary nut threaded onto a threaded extension of the piston 8 which is restrained in any suitable way against turning when the nut turns with the handwheel, so that in this way the axial position of each piston 8 can be adjusted.

The die-carrying means (FIG. 3) is in the form of a rotary plate or wheel 9 carrying all of the dies for the successive drawing passes. In the illustrated example 2 four sets 9a, Qb, 9c, 9d of three drawing dies each are carried by the rotary die-carrying means 9.' In addition,

the wheel 9 is formed with a set of three cutouts 9e also adapted to be located in the drawing plane for a purpose described below.

Thus, with the illustrated structure three tubes will be simultaneously located in side by side relation in the drawing plane to have identical operations performed thereon. On each side of the rotary die-carrying means 9 (FIG. 1b) are located rolls for moving the tubes while maintaining their axes stationary in the drawing plane, and these rolls include the rolls 1i and 11 on the left side of the Wheel 9, as viewed in FIG. 1b, with the rolls 12 on the right side thereof, these rolls 12 cooperating with the lower rolls 5a, as pointed out above. As is shown diagrammatically in FIGS. 5 and 1b, there is located adjacent to each roll 12, the latter rolls being visible at the lower part of FIG. 4, a spring-pressed roll 12d, and the several rolls 12:! respectively cooperate with the lower rolls 6a, as shown in FIG. 5, and as is illustrated in dotted lines in FIG. 1b. The cooperating pairs of rolls 6a and 12d act to position the mandrels during the drawing operations.

One of the features of the invent-ion resides in the provision of a common positioning means for simultaneously moving the rolls 11, 12 and 12d to and from their operating positions, and in addition a positioning means cooper- ;ates with the rolls 1!) for moving the latter to and from their operating positions simultaneously with the movement of the rolls 11. For this purpose the rolls 11 are carried by a bell crank 11a, the rolls 19 are carried bya lever 10a, and the rolls 12, 12d are carried by a bell crank 12a. The lever 11) fixedly carries a gear 100 which is coaxial with the journals 10b of the lever 10a, these journals being supported in suitable bearings, the lever 11a has journals 11b supported in suitable bearings, and fixedly carries a gear 110 (FIG. 1b), and the bell crank 12a is journalled at 12b and carries a gear 12c. A rack 15 meshes with the gear 100 (FIGS. 1b and 2), and this rack 15 is actuated by fluid pressure which acts on a piston 18 located in a suitable cylinder and connected coaxial to the rack 15. In accordance with the invention, a

single piston 19 slidable in a suitable cylinder is located between and fixed coaxially to a pair of racks 16 and 17 which respectively mesh with gears 13 and 14 which in turn respectively mesh with the gears 11c and 12c so that by suitable controls of the flow of fluid acting on the .pistons 18 and 19, it is possible to simultaneously move the rolls 10, 11 and 12, 12d to and from their operating positions. Of course, the racks 16 and 17 can, if desired, act directly on gears 11c and 120.

During the drawing of the tubes 3, they are supported by the rolls 29 shown in FIG. 1a, and after the last drawung pass these rolls are actuated to deposit the tubes on the conveyers 23 (FIGS. 1a, 1b, and 2) which transport the finished tubes transversely from the apparatus. These conveyers are located beneath the guides 21 for the gripping carriages 22 which in a manner well known in the art grip the leading ends of the tubes and draw the same through the dies.

As may be seen from FIG. 3, the central portion of the wheel 9 is in the form of a shaft 224a carrying a bevel gear 24 which meshes with, a bevel gear 25 driven by the shaft 26 which is operatively connected to the motor 27 to be driven thereby, and in this way the wheel 9 can be turned in the direction of the arrow 28 through preselected angular increments.

In order to drive the rolls 12 there is a driving motor 29 (FIG. 4) which is operatively connected to the rolls 12 through the transmission a, b, c, d, in the form of a gear train. The rolls 11 are driven from the motor 313 (FIG. 2) through the gear train e, f, and the rolls in are driven from the motor 31 through the gear train g, h, 1, these motors being controlled in a manner well known in the art. The above-described apparatus of the invention is operated in the following manner to perform the process of the invention:

As was pointed out above, the tubes 3 are initially placed at the upper part of the machine (PEG. 2) to be transported by the rolls 4, 4a to the upper sets of rolls 5a, 6a of the drum 1, the latter rolls cooperating with the rolls 5, 6. The drum 1 is initially positioned as shown in FIGS. 1]) and 4 so that the mandrels 2a are located at the uppermost part of the drum, and thus the tubes will in this way be placed onto the mandrels 20. Once the tubes have been placed in this way on the mandrels 2a, the entire drum 1 together with the tubes and mandrels is rotated through so that the tubes together with the mandrels 2a therein become located in the drawing plane. Thus, in the position of the parts shown in FIG. 4 the mandrels 2c are in the drawing plane, but after the drum 1 is turned through 180 from the position of FIG. 4, the

mandrels 2a, which are to be used in the first pass, become located in the drawing plane. The motor 27in the meantime is actuated so as to position the dies 94: in the drawing plane where they are respectively coaxial with the mandrels 2a, and these are the dies which are used in the first pass. a With the use of an unillustrated, known means the leading ends of the tubes are advanced through the dies 9a respectively, and they are then gripped by the drawing carriages 22 which are then actuated to draw the 'several tubes along their first pass through the dies 9a.

Once the first pass has been completed, the wheel 9 and the drum 1 are turned so as to position the cutouts 9e and the mandrels 2b in the drawing plane, and these cutouts 9e are large enough to provide free movement of the tubes therethrough. At this time the fluid-operated structures 18, 19 are actuated to bring the rolls 19-12 into their operating positions and these rolls are then driven so as to reverse the movement of the tubes while maintaining their axes stationary, and in this way the tubes will be simultaneously moved back through the openings 9e onto the mandrels 2b. When the tubes have passed through and beyond the openings 9e, the wheel 9 is turned so as to position the dies 9b in the drawing plane,

and of course the. rolls 11342 are moved from their operating positions so that they will not engage the tubes during the drawing thereof, and then the above operations are repeated with the .tubes being drawn through the dies 91) with the mandrels 2b located therein. In this way the operations are repeated for the successive mandrels 2c and 2d and the successive diesEic and 9d, and thereafter the tubes are delivered to the conveyors 23. Thus, with the structure of the invention the tubes are initially placed on the mandrels which are to be used in the first pass,

'are moved therewith to the drawing plane and drawn through the first set of dies, and once the tubes are located in the drawing plane they remain therein with their axes maintained stationary until all of the drawing operations are completed, the tubes being placed before each drawing operation on the mandrels to be used in the drawing operation, so that between each pair of passes the tubes have their direction of movement reversed while being placed on the mandrels which are to be used in the next drawing pass. Therefore, with the process and apparatus of the invention it becomes unnecessary to transport the tubes after each pass in the manner required by conventional process and apparatus and thus, particularly in the case of non-ferrous tubes, the tubes are protected against bending or other damage, and moreover the space and equipment required is less than is conventionally required while the output is greater than is provided with comparable conventional apparatus.

Of course, before each reverse movement of the tubes to place the latter on the mandrels to be used in the next following pass, the wheel 9 is turned to the position shown in FIG. 3 so that during their reverse movement the tubes always move through the cutouts 9e.

It will be understood that each of the elements described above, or two or more together, may also find a useful application in other types of metal working processes and apparatus differing from the types described above.

While the invention has been illustrated and described as embodied in a tube drawing process and apparatus, it is not intended to be limited to the details shown, since various modifications and structural changes may be made without departing in any way from the spirit of the present invention.

Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can by applying current knowledge readily adapt it for various applications without omitting features that, from the standpoint of prior art, fairly constitute essential characteristics of the generic or specific aspects of this invention and, therefore, such adaptations should and are intended to be comprehended within the meaning and range of equivalence of the following claims.

What is claimed as new and desired to be secured by Letters Patent is:

1. In a tube drawing process, the steps of drawing a tube in a pass along the axis of the tube through a first die while a first mandrel appropriate to said first die is in said tube; reversing the direction of movement of said tube after completion of said first pass while the position of the tube axis remains unchanged and passing said tube during said reverse movement thereof onto a second mandrel appropriate to a second die in preparation for a second pass; and then drawing the tube, still without changing the position of its axis, along said second pass through said second die, whereby the axis of the tube remains stationary during movement of the tube along successive drawing passes.

2. In a tube drawing process, the steps of drawing a plurality of tubes whose axes are in a common plane along a first pass simultaneously through a plurality of first dies while a plurality of first mandrels appropriate to said first dies are in said tubes, respectively; then reversing the direction of movement of said tubes after completion or" said first pass while maintaining the axes of said tubes stationary in said plane and during said reverse movement of said tubes passing the latter onto a plurality of second mandrels appropriate to a plurality of second dies to be used in a second pass; and then simultaneously drawing said tubes along said second pass through said second dies while said second mandrels are in said tubes and while maintaining the axes of said tubes stationary in said plane, whereby said tubes are drawn along successive passes without changing the positions of the axes of said tubes.

3. In a tube drawing process, the steps of drawing a tube along successive passes without changing the position of the axis of said tube; and placing said tube between each pair of successive passes on a mandrel appropriate to the next following pass while moving the tube along its axis in a direction reverse to the direction of movement of the tube during drawing thereof.

4. In a tube drawing process, the steps of passing a tube which is to be drawn onto a mandrel to be used in the first pass of the tube; then moving the tube together with the mandrel to a drawing plane; then drawing the tube in the drawing plane along the axis of the tube through a first die while said first mandrel is in said tube, to complete the first drawing pass; moving the first die away from the drawing plane and replacing the first mandrel in the drawing plane with a second mandrel to be used in the second pass; moving the tube, without changing the position of its axis, in a direction reverse to that in which it moved during the first pass, onto said second mandrel in preparation for the second pass; locating thereafter in the drawing plane the drawing die for the second pass, drawing the tube through the latter drawing die along the second pass, so that the tube after it is located in the drawing plane will be movable along the successive passes without having the position of its axis changed.

No references cited.

CHARLES W. LANHAM, Primary Examiner. 

1. IN A TUBE DRAWING PROCESS, THE STEPS OF DRAWING A TUBE IN A PASS ALONG THE AXIS OF THE TUBE THROUGH A FIRST DIE WHILE A FIRST MANDREL APPROPRIATE TO SAID FIRST DIE IS IN SAID TUBE; REVERSING THE DIRECTION OF MOVEMENT OF SAID TUBE AFTER COMPLETION OF SAID FIRST PASS WHILE THE POSITION OF THE TUBE AXIS REMAINS UNCHANGED AND PASSING SAID TUBE DURING SAID REVERSE MOVEMENT THEREOF ONTO A SECOND MANDREL APPROPRIATE TO A SECOND DIE IN PREPARATION FOR A SECOND PASS; AND THEN DRAWING THE TUBE, STILL WITHOUT CHANGING THE POSITION OF ITS AXIS, ALONG SAID SECOND PASS THROUGH SAID SECOND DIE, WHEREBY THE AXIS OF THE TUBE REMAINS STATIONARY DURING MOVEMENT OF THE TUBE ALONG SUCCESSIVE DRAWING PASSES. 